The Ecology and Productivity of Moira Atropos (Lamarck)

The ecology of the heart urchin Moira was studied in communities living at a depth of about 3 m in Biscayne Bay, Florida, Moira reaches a length of about 40 mm, 3 years after settlement, and does not grow thereafter, available energy being diverted to spawn production. There is a negative correlation between growth and temperature. Spawning is in the spring and early summer, and shows some correlation with the phase of the moon. Productivity is 3.61 g dry weight of tissue per square meter per year, of which about a third is in the form of spawn. This total is about the same value as the standing crop. By comparison, productivity is slightly less in a comparable population of Echinocardium cordatum in the Isle of Man.